JP2008216865A - Composition for forming liquid crystal alignment layer and method for manufacturing liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for forming a liquid crystal alignment layer, to form a uniform flat liquid crystal alignment layer having no stripe irregularity by a liquid droplet ejection method, and to provide a method for manufacturing a liquid crystal display device. <P>SOLUTION: The composition for forming a liquid crystal alignment layer is used to form a liquid crystal alignment layer by a liquid droplet ejection method. The composition comprises: a mixture solvent including a first organic solvent (A) having a surface tension of 32 mN/m or more and a second organic solvent (B) having a surface tension of 32 mN/m or less; and a material for forming liquid crystal alignment layer dissolved in the mixture solvent. Each of the first organic solvent (A) and the second organic solvent (B) comprises a single kind or plural kinds of organic solvents. When the boiling point of an organic solvent having the highest boiling point among the organic solvents constituting the first organic solvent (A) is represented by t<SB>max</SB>(A) and the boiling point of an organic solvent having the highest boiling point among the organic solvents constituting the second organic solvent (B) is represented by t<SB>max</SB>(B), the first organic solvent (A) and the second organic solvent (B) in the mixture solvent satisfy t<SB>max</SB>(A)>t<SB>max</SB>(B). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a composition for forming a liquid crystal alignment film used when forming a liquid crystal alignment film by a droplet discharge method, and a method for manufacturing a liquid crystal display device using the same.

  Conventionally, as a method for forming a liquid crystal alignment film in a liquid crystal display device, a flexographic printing method or a spin coating method has been generally used. However, in the flexographic printing method, the plate maintenance is complicated, and more ink than necessary is used to spread the ink on the plate, so that the ink is wasted. On the other hand, even in the spin coating method, although a large amount of ink is required, the material actually used for film formation is about 10% of the input material, and the remaining 90% is discarded. After all, there was a drawback that ink wasted a lot.

Against this background, in recent years, it has been proposed to use a droplet discharge method typified by an inkjet method as a method for forming a liquid crystal alignment film. The droplet discharge method can dispose a necessary amount of ink at a necessary location, and therefore, waste of material (ink) is small. Therefore, it is advantageous in terms of material cost and has attracted particular attention in recent years.
In order to form a liquid crystal alignment film using this droplet discharge method, a solution (a composition for forming a liquid crystal alignment film) in which a liquid crystal alignment film forming material such as polyimide or polyamic acid is dissolved in an appropriate solvent is used. Is discharged onto a substrate (liquid crystal alignment film forming surface) by a droplet discharge method and further dried to form a coating film, and then the liquid crystal alignment ability is imparted to the coating film to form a liquid crystal alignment film.

By the way, as a composition for forming a liquid crystal alignment film for forming a liquid crystal alignment film by a droplet discharge method, for example, it contains at least one of γ-butyrolactone and butyl cellosolve described in Patent Document 1, and the total content thereof Is known in which a material for forming a liquid crystal alignment film is dissolved in a solvent having an amount of 90% by weight or more based on the total amount of the solvent.
JP 2003-295195 A

However, when the composition for forming a liquid crystal alignment film described in the above document is discharged onto a substrate by a droplet discharge method to form a liquid crystal alignment film, an inkjet device (droplet discharge device) is discharged onto the formed liquid crystal alignment film. There arises a problem that vertical stripes occur along the scanning direction of the head.
As a cause of this vertical stripe unevenness,
(1) Landing position deviation due to flying flight of droplets.
(2) The drying of the liquid is fast, and the solute component (solid content) is deposited before the solutes of the droplets discharged from the adjacent nozzles are mixed.
(3) The liquid degenerates during drying.
(4) The droplet does not sufficiently wet and spread on the substrate.
And so on.
In particular, the insufficient wetting and spreading of the liquid is not limited to vertical stripes, but causes a squeeze in the edge portion of the formed liquid crystal alignment film, which becomes a major factor that the liquid crystal alignment film does not have a uniform and good film quality. The improvement is strongly desired.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a composition for forming a liquid crystal alignment film that can form a uniform and flat liquid crystal alignment film without a stripe unevenness by a droplet discharge method. And a method of manufacturing a liquid crystal display device using the composition.

The composition for forming a liquid crystal alignment film of the present invention is a composition for forming a liquid crystal alignment film used for forming a liquid crystal alignment film by a droplet discharge method, and is a first organic solvent having a surface tension of 32 mN / m or more. A mixed solvent containing A and a first organic solvent B having a surface tension of less than 32 mN / m, and a liquid crystal alignment film forming material dissolved in the mixed solvent, the first organic solvent A and the second organic solvent B are each composed of a single kind or a plurality of kinds of organic solvents, and among the organic solvents constituting the first organic solvent A, the boiling point of the organic solvent having the highest boiling point is represented by t _max ( Assuming that the boiling point of the organic solvent having the highest boiling point among the organic solvents constituting the second organic solvent B is t _max (B), the first organic solvent A and the second organic solvent in the mixed solvent B is the following expression t _max (A)> t _max (B)
It is characterized by satisfying.

  The wettability of the composition for forming a liquid crystal alignment film with respect to the substrate (liquid crystal alignment film forming surface) varies greatly depending on the type of the solvent (solvent) blended in the composition. Therefore, when adjusting the wettability of the composition for forming a liquid crystal alignment film to a desired wettability, the selection of the solvent is very important. In particular, when the aligning agent (liquid crystal alignment film forming material) is a vertical aligning agent, a long alkyl group is usually added to the side chain of the vertical aligning agent. Poor and therefore the choice of solvent becomes more important.

  In general, a solvent having a high surface tension has low wettability, and a solvent having a low surface tension has high wettability. Therefore, the first organic solvent A generally has low wettability, and the second organic solvent B generally has high wettability. Therefore, particularly when it is desired to increase the wettability with respect to the substrate, the second organic solvent B having a high wettability may be mainly blended. However, the second organic solvent B having high wettability is generally classified as a poor solvent because the solubility of the liquid crystal alignment film forming material, which is a solute, is low, and therefore the liquid crystal alignment film forming material is better dissolved. For this, it is necessary to use together the first organic solvent A, which is a good solvent for the liquid crystal alignment film forming material.

  However, when a good solvent and a poor solvent are used in combination, a uniform film may not be obtained particularly when the boiling point of the poor solvent is higher. That is, when the boiling point of the poor solvent is higher, the good solvent evaporates first in the drying process after coating, and the remaining liquid in the middle of drying becomes only the poor solvent. Then, the solid content which is a solute cannot be dissolved in the solvent, and crystallizes and precipitates during drying. As a result, the film obtained after drying will not be uniform and good, or will not be a sufficient film.

Therefore, in the present invention, as described above, the first organic solvent A, which is generally a good solvent and has low wettability, and the second organic solvent B, which is generally a poor solvent and has high wettability, are contained. While using a mixed solvent, the boiling point of the organic solvent having the highest boiling point among the organic solvents constituting the first organic solvent A is t _max (A), and among the organic solvents constituting the second organic solvent B, When the boiling point of the organic solvent having the highest boiling point is t _max (B), the mixed solvent is configured so that t _max (A)> t _max (B).
Thus, since the relationship between the maximum boiling points of the organic solvents A and B is such that t _max (A) is higher than t _max (B), the composition of the present invention is a good solvent during drying. It is prevented that all the (first organic solvent A) evaporates first and the remaining liquid in the middle of drying becomes only the poor solvent (second organic solvent B). Thereby, it is prevented that solid content which is a solute crystallizes and precipitates during drying, and the film obtained after drying becomes uniform and good.

Further, as described above, a mixed solvent containing the first organic solvent A that is generally a good solvent and has low wettability and the second organic solvent B that is generally poor and has high wettability is used. Therefore, the use of the second organic solvent B having particularly high wettability suppresses inconvenience that the obtained liquid crystal alignment film oozes at the edge portion as well as vertical stripe unevenness, and the first is low in wettability. By using the organic solvent A, it is possible to reduce the possibility that the adjacent liquid droplets stick to each other due to excessive wetting and the liquid crystal alignment film to be obtained is not uniformly formed with a desired thickness.
Therefore, according to this composition for forming a liquid crystal alignment film, a uniform and flat liquid crystal alignment film without streaks can be obtained by disposing on the substrate (liquid crystal alignment film forming surface) by a droplet discharge method. In addition, since the swelling (bump) at the edge portion of the liquid crystal alignment film is reduced, a high-quality liquid crystal alignment film can be efficiently formed.

In the composition for forming a liquid crystal alignment film, the mixing ratio of the second organic solvent B in the entire mixed solvent is preferably 1% by weight or more and 50% by weight or less.
By blending 1% by weight or more of the second organic solvent B having high wettability, good wettability with respect to the substrate (liquid crystal alignment film forming surface) of the liquid crystal alignment film forming composition is ensured. In addition, by setting the content to 50% by weight or less, the second organic solvent B, which is a poor solvent, does not occupy the majority of the mixed solvent, thereby ensuring good solubility of the mixed solvent in the liquid crystal alignment film forming material. The

In the composition for forming a liquid crystal alignment film, the first organic solvent A includes N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N, N-dimethyl-2-imidazolidinone, N , N-dimethyl-acetamide, γ-butyrolactone, and at least one selected from the group consisting of propylene carbonate.
Each of the above-mentioned solvents is a good solvent having better solubility in the liquid crystal alignment film forming material. Therefore, by using at least one of these, a better mixed solvent for the liquid crystal alignment film forming material is obtained. Solubility is ensured.

In the composition for forming a liquid crystal alignment film, the second organic solvent B is composed of 1-methoxy-2-propanol, 1-methoxy-2-acetoxypropane, butyl cellosolve, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether. It is preferably at least one selected from the group.
Each of these solvents can improve the formation of the liquid crystal alignment film as confirmed by the experimental results described later.

In the composition for forming a liquid crystal alignment film, the solid content concentration of the material for forming a liquid crystal alignment film is 1 wt% or more and 10 wt% or less, and the viscosity is 3 mPa · s or more and 20 mPa · s or less, The surface tension is preferably adjusted to 30 mN / m or more and 45 mN / m or less.
This is because if the solid content concentration is less than 1% by weight, the resulting alignment film is too thin and may not be a good liquid crystal alignment film. If the solid content concentration exceeds 10% by weight, The resulting alignment film is too thick, and may not be a good liquid crystal alignment film. Also, the viscosity of the composition for forming a liquid crystal alignment film increases, and the discharge performance by the droplet discharge method decreases. It is.
In addition, by adjusting the viscosity to 3 mPa · s or more and 20 mPa · s or less, the fluidity is improved, and therefore a good and stable discharge property by the droplet discharge method can be ensured. Furthermore, by adjusting the surface tension to 30 mN / m or more and 45 mN / m or less, the wettability to the substrate surface is improved, and therefore a liquid crystal alignment film having a uniform thickness can be efficiently formed by a droplet discharge method. .

（式中、Ｐ^１は４価の有機基であり、Ｑ^１は２価の有機基を表す。）で示される繰り返し単位、および以下の式（II）

（式中、Ｐ^２は４価の有機基であり、Ｑ^２は２価の有機基を表す。）で示される繰り返し単位から選ばれる、少なくとも一種を有する重合体であるのが好ましい。 In the composition for forming a liquid crystal alignment film, the material for forming a liquid crystal alignment film is represented by the following formula (I):

(Wherein P ¹ is a tetravalent organic group, Q ¹ represents a divalent organic group), and the following formula (II)

(In the formula, P ² is a tetravalent organic group, and Q ² represents a divalent organic group.) A polymer having at least one selected from repeating units represented by

The method for producing a liquid crystal display device of the present invention is characterized by having a step of forming the liquid crystal alignment film by applying the liquid crystal alignment film forming composition to the substrate surface by a droplet discharge method.
According to this manufacturing method, a uniform and flat liquid crystal alignment film without streaks can be obtained, so that a high-quality liquid crystal display device can be efficiently manufactured at low cost.

The present invention will be described in detail below.
First, the liquid crystal alignment film forming composition of the present invention will be described.
The composition for forming a liquid crystal alignment film of the present invention (hereinafter sometimes referred to as “the composition of the present invention”) is an ink used for forming a liquid crystal alignment film by a droplet discharge method using a droplet discharge device. A liquid crystal alignment film formed by dissolving a mixed solvent containing a first organic solvent A having a surface tension of 32 mN / m or more and a first organic solvent B having a surface tension of less than 32 mN / m, and the mixed solvent. And a forming material.

The first organic solvent A and the second organic solvent B are each constituted by a single type or a plurality of types of organic solvents. Of the organic solvents constituting the first organic solvent A, the boiling point of the organic solvent having the highest boiling point is t _max (A), and the boiling point of the organic solvents constituting the second organic solvent B is When the highest boiling point of the organic solvent is t _max (B), the first organic solvent A and the second organic solvent B in the mixed solvent are expressed by the following formula: t _max (A)> t _max (B)
Is appropriately selected and blended so as to satisfy the above.

First, specific examples of the mixed solvent will be described.
(Mixed solvent)
In the composition of the present invention, a first organic solvent A having a surface tension of 32 mN / m or more and a first organic solvent B having a surface tension of less than 32 mN / m are used as a solvent for dissolving the liquid crystal alignment film forming material. These are mixed to form a mixed solvent.

  The first organic solvent A is an aprotic polar solvent or a phenol solvent, and at least one solvent having a surface tension of 32 mN / m or more is selected and used. Examples of the aprotic polar solvent include amide solvents, sulfoxide solvents, ether solvents, nitrile solvents, and the like. Of these, amide solvents and sulfoxide solvents are preferably used from the viewpoint of efficiently forming a high-quality liquid crystal alignment film having no smoothness and excellent smoothness.

Examples of the amide solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoramide, tetramethylurea and the like.
Examples of the sulfoxide solvent include dimethyl sulfoxide and diethyl sulfoxide.

Examples of the phenolic solvent include cresols such as o-cresol, m-cresol, and p-cresol; xylenols such as o-xylenol, m-xylenol, and p-xylenol; phenol; o-chlorophenol, m-chlorophenol, halogenated phenols such as o-bromophenol and m-bromophenol;
Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N, N-dimethyl-2-imidazolidinone, N, N-dimethyl-acetamide, γ-butyrolactone, and propylene carbonate At least one selected from the above is preferably used.
Here, the boiling point t (A) and the surface tension at 25 ° C. of these solvents are as follows.
N-methyl-2-pyrrolidone:
Boiling point: 204 ° C. Surface tension: 41 mN / m
N-ethyl-2-pyrrolidone:
Boiling point: 218 ° C Surface tension: 40 mN / m
N, N-dimethyl-2-imidazolidinone:
Boiling point: 225 ° C. Surface tension: 38.6 mN / m
N, N-dimethyl-acetamide:
Boiling point: 166 ° C. Surface tension: 32.4 mN / m
・ Γ-butyrolactone:
Boiling point: 204 ° C. Surface tension: 44 mN / m
・ Propylene carbonate:
Boiling point: 242 ° C Surface tension: 40.9 mN / m

These solvents are good solvents having better solubility in the liquid crystal alignment film forming material to be described later. Therefore, by using at least one of them, the mixed solvent for the liquid crystal alignment film forming material is better. High solubility can be ensured.
Here, the first organic solvent A having a surface tension of 32 mN / m or more and a relatively large surface tension as described above has low wettability with respect to the substrate surface, which is the formation surface of the liquid crystal alignment film. Therefore, when only this first organic solvent A is blended, the composition blended with only this has poor wettability with respect to the substrate surface, and sufficient film formation cannot be performed.

Therefore, in the composition of the present invention, a solvent containing the second organic solvent B having a relatively small surface tension of less than 32 mN / m and thus good wettability is used as the mixed solvent. As the second organic solvent B, as described above, at least one solvent having a surface tension of less than 32 mN / m is selected and used.
Specifically, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), 1-methoxy-2-propanol, 1-methoxy-2-acetoxypropane Alcohol solvents such as ethylene glycol, propylene glycol, 1,4-butanediol and triethylene glycol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethylene glycol monomethyl ether, diethyl ether, ethylene glycol methyl ether , Ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol-n-butyl ether Ether solvents such as ter (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran; Ester solvents such as ethyl, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate; dichloromethane, 1,2-dichloroethane, 1,4 -Dichlorobutane, trichloroethane, chlorbe Halogenated hydrocarbon solvents such as zen and o-dichlorobenzene; aliphatic hydrocarbon solvents such as n-hexane, n-heptane and n-octane; aromatic hydrocarbon solvents such as benzene, toluene and xylene; Etc. These solvents can be used alone or in combination of two or more.

Among these, at least one selected from the group consisting of 1-methoxy-2-propanol, 1-methoxy-2-acetoxypropane, butyl cellosolve, and diethylene glycol diethyl ether is preferably used.
Here, the boiling point t (A) and the surface tension at 25 ° C. of these solvents are as follows.
1-methoxy-2-propanol Boiling point: 120 ° C. Surface tension: 27.7 mN / m
1-methoxy-2-acetoxypropane Boiling point: 145 ° C. Surface tension: 26.7 mN / m
Butyl cellosolve Boiling point: 170 ° C. Surface tension: 27.4 mN / m
Diethylene glycol ethyl methyl ether Boiling point: 176 ° C. Surface tension: 26.8 mN / m
Diethylene glycol diethyl ether Boiling point: 188 ° C. Surface tension: 29.7 mN / m

  These solvents do not show good solubility in the liquid crystal alignment film forming material described later, and thus become poor solvents, but have high wettability with respect to the substrate surface as described above. Uniformly forming a liquid crystal alignment film having a desired thickness by preventing vertical unevenness due to insufficient wetting and spreading of the film-forming composition and swelling (raising) at the edge of the liquid crystal alignment film formed. Can do.

  The mixing ratio of the second organic solvent B to the entire mixed solvent is preferably 1% by weight or more and 50% by weight or less. By blending 1% by weight or more of the second organic solvent B having high wettability, it is possible to ensure good wettability with respect to the substrate (liquid crystal alignment film forming surface) of the liquid crystal alignment film forming composition. Therefore, it is possible to form a uniform and flat liquid crystal alignment film. Moreover, the second organic solvent B, which is a poor solvent, does not occupy the majority of the mixed solvent by setting it to 50% by weight or less, thereby ensuring good solubility of the mixed solvent in the liquid crystal alignment film forming material. Good film formability can be obtained.

In addition, the mixed solvent containing the first organic solvent A and the second organic solvent B has the _maximum boiling point of the organic solvent constituting the first organic solvent A t _max ( Assuming that the _maximum boiling point of the organic solvent constituting the second organic solvent B is t _max (B), t _max (A)> t _max (B). ,It is configured.
Thus, since the relationship between the maximum boiling points of the organic solvents A and B is such that t _max (A) is higher than t _max (B), the composition of the present invention is a good solvent during drying. It is prevented that all the (first organic solvent A) evaporates first and the remaining liquid in the middle of drying becomes only the poor solvent (second organic solvent B). Thereby, it is prevented that solid content which is a solute crystallizes and precipitates during drying, and the film obtained after drying becomes uniform and good.

Next, the liquid crystal alignment film forming material that is dissolved in the mixed solvent and has a solid content will be described.
(Liquid crystal alignment material)
The material for forming a liquid crystal alignment film used in the composition of the present invention is not particularly limited, and a conventionally known material for forming a liquid crystal alignment film can be used. Examples thereof include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polysiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, and the like.

  Among these, it has at least one selected from the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) for the reason that an alignment film having excellent liquid crystal alignment ability can be formed. A polymer is preferred.

  Examples of such a polymer include (i) a polyamic acid having a repeating unit represented by the formula (I), (ii) an imidized polymer having a repeating unit represented by the formula (II), Examples thereof include a block copolymer having an amic acid prepolymer having a repeating unit represented by the formula (I) and an imide prepolymer having a repeating unit represented by the formula (II). These may be used alone or in combination of two or more. When using in combination of 2 or more types, it is preferable to mix and use a polyamic acid and an imidized polymer.

(I) Polyamic acid A polyamic acid can be obtained by reacting a tetracarboxylic dianhydride and a diamine.
Examples of tetracarboxylic dianhydrides used for the synthesis of polyamic acid include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride. Anhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2 , 3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexane Tetracarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracar Acid dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 2,3, 4,5-tetrahydrofurantetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]- Furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]- Furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]- Furan-1,3-dione, 1,3,3a , 4,5,9b-Hexahydro-7-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a , 4,5,9b-Hexahydro-7-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a , 4,5,9b-Hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a , 4,5,9b-Hexahydro-8-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a , 4,5,9b-Hexahydro-5,8-dimethyl-5 (tetra Dro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene -1,2-dicarboxylic dianhydride, bicyclo [2,2,2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxabicyclo [3,2, 1] Alicyclic tetracarboxylic acid such as octane-2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), compounds represented by the following formulas (1) and (2) Dianhydride;

（式中、Ｒ^４、Ｒ^５、Ｒ^７及びＲ^８は、それぞれ独立して水素原子又はアルキル基を表し、Ｒ^６及びＲ^９は、それぞれ独立して芳香環を有する２価の有機基を表す。）

(In the formula, R ⁴ , R ⁵ , R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group, and R ⁶ and R ⁹ each independently represent a divalent organic group having an aromatic ring. To express.)

Aliphatic tetracarboxylic dianhydrides such as butanetetracarboxylic dianhydride;
Pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis ( 3,4-dicar Boxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (Phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4 , 4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride, ethylene glycol-bis (anhydro trimellitate), propylene glycol-bis (anhydro trimellitate) 1,4-butanediol-bis (anhydrotrimellitate), 1,6-hexanediol-bis (anhydride) Trimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate), the following formulas (3) to (6) An aromatic tetracarboxylic dianhydride such as an aromatic tetracarboxylic dianhydride having a steroid skeleton represented by These can be used alone or in combination of two or more.

  Examples of the diamine used for the synthesis of polyamic acid include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl sulfide, 4, 4'-diaminodiphenyl sulfone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 4,4 ' -Diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 6- Amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 3,4′-diaminodiphenyl ether 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene 2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4′-methylene-bis (2-chloro) Nilin), 2,2 ′, 5,5′-tetrachloro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5,5′-dimethoxybiphenyl, 3,3 ′ -Dimethoxy-4,4'-diaminobiphenyl, 1,4,4 '-(p-phenyleneisopropylidene) bisaniline, 4,4'-(m-phenyleneisopropylidene) bisaniline, 2,2'-bis [4- (4-Amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino- Aromatic diamines such as 2-trifluoromethyl) phenoxy] -octafluorobiphenyl;

  1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophorone diamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene methylene diamine, tricyclo [6.2.1.02,7] -undecylenedimethyl diamine, 4, Aliphatic and cycloaliphatic diamines such as 4'-methylenebis (cyclohexylamine);

  2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino-2,4 -Dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3 , 5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl -S-triazine, 2,4-diamino-1,3,5-triazine, 4,6-diamino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6- Aminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6 Two primary amino groups in the molecule, such as phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, and nitrogen atoms other than the primary amino group A diamine having the formula:

（式中、Ｒ^１０〜Ｒ^１３は、それぞれ独立して炭素数１〜１２の炭化水素基を表し、ｐ、ｒはそれぞれ独立して１〜３の整数であり、ｑは１〜２０の整数である。）で示されるジアミノオルガノシロキサン等が挙げられる。これらのジアミンは一種単独で、あるいは二種以上を組み合わせて用いることができる。

(Wherein R ^{10 to} R ¹³ each independently represent a hydrocarbon group having 1 to 12 carbon atoms, p and r are each independently an integer of 1 to 3, and q is an integer of 1 to 20) And the like, and the like. These diamines can be used alone or in combination of two or more.

When it is desired to impart pretilt angle expression to the composition of the present invention, a part or all of Q ¹ in the above formula (I) and / or Q ² in the above formula (II) is represented by the following formula (8) and It is preferably at least one group represented by (9).

（式中、Ｘ^１は、単結合、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨＣＯ−、−ＣＯＮＨ−、−Ｓ−又はアリーレン基であり、Ｒ^１４は、炭素数１０〜２０のアルキル基、炭素数４〜４０の脂環式骨格を有する１価の有機基又は炭素数６〜２０のフッ素原子を有する１価の有機基である。）

(In the formula, X ¹ represents a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S— or an arylene group, and R ¹⁴ represents the number of carbon atoms. A 10-20 alkyl group, a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, or a monovalent organic group having a fluorine atom having 6 to 20 carbon atoms.)

（式中、Ｘ^２、Ｘ^３はそれぞれ独立して、単結合、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨＣＯ−、−ＣＯＮＨ−、−Ｓ−又はアリーレン基であり、Ｒ^１５は、炭素数４〜４０の脂環式骨格を有する２価の有機基である。）

Wherein X ² and X ³ are each independently a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S— or an arylene group. R ¹⁵ is a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms.)

In the formula (8), examples of the alkyl group having 10 to 20 carbon atoms represented by R ¹⁴ include an n-decyl group, an n-dodecyl group, an n-pentadecyl group, an n-hexadecyl group, and an n-octadecyl group. , N-eicosyl group and the like.

Examples of the organic group having an alicyclic skeleton having 4 to 40 carbon atoms represented by R ¹⁴ in the formula (8) and R ¹⁵ in the formula (9) include cyclobutane, cyclopentane, cyclohexane, A group having a cycloalkane-derived alicyclic skeleton such as cyclodecane; a group having a steroid skeleton such as cholesterol or cholestanol; a group having a bridged alicyclic skeleton such as norbornene or adamantane. The organic group having an alicyclic skeleton may be a group substituted with a halogen atom, preferably a fluorine atom, or a fluoroalkyl group, preferably a trifluoromethyl group.

Furthermore, examples of the organic group having a fluorine atom having 6 to 20 carbon atoms represented by R ¹⁴ in the formula (8) include 6 carbon atoms such as an n-hexyl group, an n-octyl group, and an n-decyl group. In the above linear alkyl group; an alicyclic hydrocarbon group having 6 or more carbon atoms such as a cyclohexyl group or a cyclooctyl group; an organic group such as an aromatic hydrocarbon group having 6 or more carbon atoms such as a phenyl group or a biphenyl group Examples include a group in which part or all of the hydrogen atoms are substituted with a fluorine atom or a fluoroalkyl group such as a trifluoromethyl group.

As the arylene group ^X 1 to X ³ in the formula (8) and (9), a phenylene group, a tolylene group, a biphenylene group, and naphthylene group.

  Specific examples of the diamine having the group represented by the formula (8) include dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy-2, Preferred examples include 4-diaminobenzene and compounds represented by the following formulas (10) to (15).

  Specific examples of the diamine having a group represented by the formula (9) include diamines represented by the following formulas (16) to (18).

  The use ratio of the specific diamine with respect to the total amount of diamine varies depending on the size of the pretilt angle to be expressed. 5 to 100 mol% is preferable.

  The polyamic acid can be produced by reacting the above-described tetracarboxylic dianhydride and diamine in an appropriate organic solvent, usually at -20 ° C to + 150 ° C, preferably 0 to 100 ° C.

  The proportion of tetracarboxylic dianhydride and diamine used is preferably such that the proportion of the acid anhydride group of tetracarboxylic dianhydride is 0.2 to 2 equivalents relative to 1 equivalent of amino group of diamine. Is a ratio of 0.3 to 1.2 equivalents.

  The organic solvent used for the polyamic acid synthesis reaction is not particularly limited as long as it can dissolve the polyamic acid. For example, aprotic polar solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide; And phenolic solvents such as cresol, xylenol, phenol and halogenated phenol;

  The amount of organic solvent used (α) is usually such that the total amount (β) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight based on the total amount of the reaction solution (α + β). It is preferable that

  In addition, the poor solvent of a polyamic acid can be used together with the said organic solvent in the range in which the polyamic acid to produce | generate does not precipitate.

  Examples of the poor solvent for the polyamic acid include those exemplified as the poor solvent for the material for forming a liquid crystal alignment film. These solvents can be used alone or in combination of two or more.

A polyamic acid can be isolated by pouring a reaction solution containing a polyamic acid into a large amount of poor solvent to obtain a precipitate, and drying the precipitate under reduced pressure.
Moreover, a polyamic acid can be refine | purified by performing the process made to melt | dissolve the obtained polyamic acid in an organic solvent again, and to precipitate with a poor solvent once or several times.

(Ii) Imidized polymer The imidized polymer can be obtained by dehydrating and ring-closing the polyamic acid by a known method, for example, a method described in JP-A No. 2003-295195. In the imidized polymer, 100% of the repeating units may not be dehydrated and closed, and the ratio of the repeating units having an imide ring in all the repeating units (hereinafter also referred to as “imidation rate”) is 100%. It may be less.

  The imidation rate of the imidized polymer is not particularly limited, but is preferably 40 mol% or more, more preferably 70 mol% or more. By using a polymer having an imidization ratio of 40 mol% or more, a liquid crystal alignment film forming composition capable of forming a liquid crystal alignment film having a short afterimage erasing time can be obtained.

  The polymer used in the present invention may be a terminal-modified type having a controlled molecular weight. By using this terminal-modified polymer, it is possible to improve the application suitability of the composition for forming a liquid crystal alignment film without impairing the effects of the present invention.

  Such a terminal-modified polymer can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing a polyamic acid. Here, examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride. , N-hexadecyl succinic anhydride and the like. Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, and n-undecylamine. , N-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine and the like. . Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

(Iii) Block copolymer The block copolymer synthesizes an amic acid prepolymer having an amino group or an acid anhydride group at the terminal and an imide prepolymer having an acid anhydride group or an amino group at the terminal, It can be obtained by bonding an amino group at the end of each prepolymer and an acid anhydride group.

  The amic acid prepolymer can be synthesized by the same method as the polyamic acid synthesis method described above. Further, the imide prepolymer can be synthesized in the same manner as the above-described imidized polymer synthesis method. The functional group at the end can be selected by adjusting the amounts of tetracarboxylic dianhydride and diamine during polyamic acid synthesis.

  In order to improve the adhesion to the substrate surface, the composition of the present invention may contain a functional silane-containing compound or an epoxy group-containing compound in addition to the mixed solvent and the liquid crystal alignment film forming material.

  There are no particular limitations on the functional silane-containing compound and epoxy group-containing compound used, and conventionally known compounds can be used. The mixing ratio of these functional silane-containing compound and epoxy group-containing compound is usually 40 parts by weight or less, preferably 30 parts by weight or less, with respect to 100 parts by weight of the liquid crystal alignment film forming material.

  The composition of the present invention can be produced by dissolving or dispersing, preferably dissolving, the liquid crystal alignment film-forming material and optionally a functional silane-containing compound in the mixed solvent.

  The solid content concentration of the liquid crystal alignment film-forming material in the composition of the present invention is selected in consideration of viscosity, surface tension, etc., but is preferably in the range of 1 wt% to 10 wt%. The This is because if the solid content concentration is less than 1% by weight, the resulting alignment film is too thin and may not be a good liquid crystal alignment film. In addition, if the solid content concentration exceeds 10% by weight, the resulting alignment film becomes too thick, which may not be a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment film forming composition increases. This is because the discharge performance by the droplet discharge method is lowered.

Although it does not restrict | limit especially about the viscosity of this invention composition, It is preferable to adjust to the range of 3 mPa * s or more and 20 mPa * s or less (20 degreeC). By adjusting the viscosity within this range, the fluidity is improved, and therefore a good and stable ejection property by the droplet ejection method can be ensured.
Further, the surface tension of the composition of the present invention is not particularly limited, but it is preferably adjusted in the range of 30 mN / m to 45 mN / m (20 ° C.). By adjusting the surface tension within this range, the wettability to the substrate surface is improved, and therefore a liquid crystal alignment film having a uniform thickness can be efficiently formed by the droplet discharge method.

  According to the composition of the present invention, it is possible to obtain a uniform and flat liquid crystal alignment film without streaks as described above by disposing on the substrate (liquid crystal alignment film forming surface) by a droplet discharge method. Since the swelling (bump) at the edge portion of the liquid crystal alignment film is reduced, a high-quality liquid crystal alignment film can be efficiently formed. Therefore, even when a vertical alignment agent having very poor wettability to a substrate, that is, a liquid crystal alignment film forming composition for a liquid crystal having a negative dielectric anisotropy is used, the liquid crystal alignment film formation of the present invention containing the same is used. The composition for use has sufficiently good wettability, which makes it possible to form a high-quality liquid crystal alignment film. Therefore, a high-quality liquid crystal display device can be manufactured by using the composition for forming a liquid crystal alignment film of the present invention.

Next, the manufacturing method of the liquid crystal display device using the composition for liquid crystal aligning film formation of this invention is demonstrated.
The method for producing a liquid crystal display device of the present invention includes a step of applying the above-described composition of the present invention to the substrate surface by a droplet discharge method to form a liquid crystal alignment film.

The method for producing a liquid crystal display device of the present invention can be carried out, for example, using the production line for the liquid crystal display device shown in FIG.
As shown in FIG. 1, the liquid crystal display device production line I includes a cleaning device 1, a lyophilic processing device 2, a droplet discharge device 3a, a drying device 4, a baking device 5, a rubbing device 6, a liquid used in each process. A droplet discharge device 3b, a droplet discharge device 3c, a bonding device 7, a belt conveyor A connecting the devices, a drive device 8 for driving the belt conveyor A, and a control device 9 for controlling the entire liquid crystal display device production line I It is comprised by.

  An example of a droplet discharge device used in the present invention is shown in FIG. FIG. 2 is a diagram showing an outline of the configuration of the ink jet type ejection device 3a. The discharge device 3a is not particularly limited as long as it is a so-called inkjet discharge device. For example, there are a piezo-type discharge device that discharges droplets by compression using a piezo element, a thermal-type discharge device that generates bubbles by heating and foaming and discharges droplets, and the like.

  The discharge device 3a includes an inkjet head 22 that discharges a discharge (the composition of the present invention) onto a substrate. The ink jet head 22 includes a head main body 24 and a nozzle forming surface 26 on which a large number of nozzles for discharging discharged matter are formed. From the nozzle of the nozzle forming surface 26, the above-described composition of the present invention is discharged onto the substrate.

  The discharge device 3a includes a table 28 on which a substrate is placed. The table 28 is installed to be movable in a predetermined direction, for example, the X-axis direction, the Y-axis direction, and the Z-axis direction. Further, the table 28 moves in the direction along the X axis as indicated by an arrow in the drawing, whereby the substrate conveyed by the belt conveyor A is placed on the table 28 and taken into the discharge device 3a.

  The ink jet head 22 is connected to a tank 30 that contains a discharge material discharged from a nozzle formed on the nozzle forming surface 26. In other words, the tank 30 and the inkjet head 22 are connected by a discharge material transport pipe 32 that transports the discharge material.

  The discharge material transfer pipe 32 includes a discharge material flow path portion ground joint 32a and a head portion bubble elimination valve 32b for preventing charging in the flow path of the discharge material transfer pipe 32. This head part bubble elimination valve 32b is used when suctioning the discharged substance in the inkjet head 22 with the suction cap 40 mentioned later. That is, when sucking the discharged material in the inkjet head 22 by the suction cap 40, the head part bubble elimination valve 32b is closed, and the discharged material does not flow from the tank 30 side. Then, when suction is performed with the suction cap 40, the flow rate of the suctioned product is increased, and the bubbles in the inkjet head 22 are quickly discharged.

  The discharge device 3a is a liquid for controlling the storage amount of the discharge material stored in the tank 30, that is, the height of the liquid surface 34a of the discharge material (the composition of the present invention) stored in the tank 30. A surface control sensor 36 is provided. The liquid level control sensor 36 keeps the height difference h (hereinafter referred to as the water head value) between the tip 27 of the nozzle forming surface 26 of the inkjet head 22 and the liquid level 34a in the tank 30 within a predetermined range. Take control. By controlling the height of the liquid level 34a, the discharge 34 in the tank 30 is sent to the inkjet head 22 with a pressure within a predetermined range. Then, the ejected material 34 can be stably ejected from the inkjet head 22 by sending the ejected material 34 at a pressure within a predetermined range.

In addition, a suction cap 40 that sucks the ejected matter in the nozzles of the inkjet head 22 is disposed at a certain distance from the nozzle formation surface 26 of the inkjet head 22. The suction cap 40 is configured to be movable in a direction along the Z axis indicated by an arrow in FIG. 3, and the nozzle forming surface 26 surrounds a plurality of nozzles formed on the nozzle forming surface 26.
The nozzle can be blocked from outside air by forming a sealed space between the nozzle forming surface 26 and the nozzle forming surface 26.

  In addition, the suction of the ejected matter in the nozzles of the ink jet head 22 by the suction cap 40 is performed when the ink jet head 22 is not ejecting the ejected matter 34, for example, the ink jet head 22 is retracted to a retracted position or the like This is performed when 28 is retracted to a position indicated by a broken line.

A flow path is provided below the suction cap 40, and a suction valve 42, a suction pressure detection sensor 44 for detecting a suction abnormality, and a suction pump 46 including a tube pump are disposed in the flow path. Has been. Further, the discharge 34 sucked by the suction pump 46 and transported through the flow path is accommodated in a waste liquid tank 48.
In the following description, the droplet discharge devices 3b and 3c have the same configuration as the discharge device 3a except that the materials to be discharged are different.

Next, the present invention will be described in detail taking as an example the case of manufacturing the liquid crystal display device shown in FIG. FIG. 3 is a diagram schematically showing a cross section of the liquid crystal display device manufactured according to this embodiment.
The liquid crystal display device shown in FIG. 3 is a passive matrix transflective color liquid crystal display device. In the liquid crystal display device 50, a rectangular flat plate-like lower substrate 52a made of glass, plastic, or the like and an upper substrate 52b are arranged to face each other via a sealant and a spacer (not shown), and the lower substrate 52a and the upper substrate 52b. A liquid crystal layer 56 is sandwiched therebetween.

  A plurality of segment electrodes 58 and a liquid crystal alignment film 60 are formed between the lower substrate 52a and the liquid crystal layer 56 from the lower substrate 52a side. As shown in FIG. 3, the segment electrode 58 is formed in a stripe shape, and is formed of a transparent conductive film such as indium tin oxide (hereinafter referred to as “ITO”). The liquid crystal alignment film 60 is formed of a liquid crystal alignment film forming material.

  A color filter 62, an overcoat film 66, a common electrode 68, and a liquid crystal alignment film 70 are formed between the upper substrate 52b and the liquid crystal layer 56 in this order from the upper substrate 52b side. The color filter 62 includes red (R), green (G), and blue (B) dye layers 62r, 62g, and 62b. Between the dye layers 62r, 62g, and 62b included in the color filter 62, the color filter 62 is provided. On the (boundary), a black matrix 64 made of metal such as resin black or chromium (Cr) having low light reflectance is formed. The dye layers 62r, 62g, and 62b constituting the color filter 62 are disposed so as to face the segment electrodes 58 formed on the lower substrate 52a.

The overcoat film 66 flattens the steps between the dye layers 62r, 62g, and 62b and protects the surface of each dye layer, and is formed of an inorganic film such as an acrylic resin, a polyimide resin, or a silicon oxide film. ing.
The common electrode 68 is formed of a transparent conductive film such as ITO, and is formed in a stripe shape at a position orthogonal to the segment electrode 58 formed on the lower substrate 52a.
The liquid crystal alignment film 70 is formed of a polyimide resin or the like.

  The liquid crystal display device shown in FIG. 3 can be manufactured through steps (S10) to (S19) as shown in FIG. Hereinafter, each step will be described in order.

(S10)
First, a substrate for forming a liquid crystal alignment film is prepared.
As the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, or polycarbonate can be used. As the transparent conductive film provided on one surface of the substrate, a film made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), or the like can be used. For patterning these transparent conductive films, a photo-etching method or a method using a mask in advance is used. In the present embodiment, the lower substrate 52a on which the segment electrode 58 is formed is used.

Next, the surface of the substrate on which the alignment film is formed is washed (S10). That is, the lower substrate 52a on which the segment electrode 58 is formed is transported to the cleaning device 1 by the belt conveyor A, and the lower substrate 52a transported by the belt conveyor A is taken into the cleaning device 1, and an alkaline detergent, pure water After the lower substrate 52a is cleaned using, for example, a drying process is performed at a predetermined temperature and time, for example, at 80 to 90 ° C. for 5 to 10 minutes.
The lower substrate 52a that has been cleaned and dried is conveyed to the lyophilic processing apparatus 2 by the belt conveyor A.

(S11)
Next, the cleaned and dried substrate surface is subjected to a lyophilic process (S11). That is, the substrate, for example, the lower substrate 52a, transported to the lyophilic processing device 2 by the belt conveyor A is taken into the lyophilic processing device 2, and the surface is lyophilicized by ultraviolet irradiation or plasma processing. By performing the lyophilic treatment, the wettability of the composition for forming a liquid crystal alignment film (the composition of the present invention) is further improved, and a liquid crystal alignment film that is more uniform, flat and excellent in adhesion can be formed on the substrate. it can.

(S12)
Next, the composition of the present invention is applied on the lyophilic substrate in S11 (S12). That is, first, a substrate, for example, the lower substrate 52a, transported to the droplet discharge device 3a by the belt conveyor A is placed on the table 28 and taken into the droplet discharge device 3a. In the droplet discharge device 3a, the composition of the present invention stored in the tank 30 is discharged through the nozzles of the nozzle forming surface 26, and the composition of the present invention is applied onto the lower substrate 52a.

(S13)
Next, a process of temporarily drying the composition of the present invention applied to the substrate is performed (S13). That is, the board | substrate conveyed to the drying apparatus 4 by the belt conveyor A, for example, the lower board | substrate 52a, is taken in in the drying apparatus 4, and temporary drying is performed at 60-200 degreeC, for example.
The lower substrate 52a on which the applied composition of the present invention has been preliminarily dried is transferred to the belt conveyor A and conveyed to the baking apparatus 5 by the belt conveyor A.

(S14)
Next, the process of baking this invention composition by which temporary drying was performed is performed (S14). That is, the substrate conveyed to the baking apparatus 5 by the belt conveyor A, for example, the lower substrate 52a is taken into the baking apparatus 5 and is subjected to a process of baking to 180 to 250 ° C., for example.

In addition, when using the composition for liquid crystal aligning film formation (this invention composition) containing a polyamic acid, spin-drying | dehydration cyclization advances by this baking process and it may become a more imidized coating film. .
The film thickness of the coating film to be formed is usually 0.001 to 1 μm, preferably 0.005 to 0.5 μm.
As described above, as shown in FIG. 5, the lower substrate 52a on which the coating film 60a of the composition of the present invention is formed is obtained.
The lower substrate 52a is transferred to the belt conveyor A, and is conveyed to the rubbing device 6 by the belt conveyor A.

(S15)
Next, the rubbing process of the coating film 60a of the composition of the present invention formed on the substrate is performed (S15). In other words, a substrate conveyed to the rubbing device 6 by the belt conveyor A, for example, the lower substrate 52a is taken into the rubbing device 6 and rubbed in a certain direction with a roll wound with a cloth made of, for example, nylon, rayon, cotton or the like. Rubbing is performed. Thereby, as shown in FIG. 6, the alignment ability of the liquid crystal molecules is imparted to the coating film, and the liquid crystal alignment film 60 is formed.

  Further, a pretilt angle is obtained by partially irradiating a liquid crystal alignment film formed of the composition of the present invention with ultraviolet rays as disclosed in, for example, JP-A-6-222366 and JP-A-6-281937. A resist film is partially formed on the surface of the liquid crystal alignment film that has been subjected to rubbing treatment, as shown in Japanese Patent Application Laid-Open No. 5-107544, in a direction different from the previous rubbing treatment. The visibility characteristics of the liquid crystal display element can be improved by removing the resist film after the rubbing process and performing a process for changing the liquid crystal alignment ability of the liquid crystal alignment film.

(S16)
The lower substrate 52a on which the liquid crystal alignment film 60 is formed is transferred to the belt conveyor A, conveyed to the droplet discharge device 3b by the belt conveyor A, and taken into the droplet discharge device 3b. In the droplet discharge device 3b, as shown in FIGS. 7A and 7B, a seal layer forming solution is applied so as to surround the liquid crystal display region B on the rubbed liquid crystal alignment film 60. (S16). In FIG. 7, 59a is a coating film of the seal layer forming solution. 7A is a top view of the process, and FIG. 7B is a cross-sectional view of the process as viewed from the horizontal direction.

  Here, as the solution for forming the seal layer, a conventionally known adhesive can be used as an adhesive for joining the lower substrate and the upper substrate. For example, droplets containing an ionizing radiation curable resin (ionizing radiation curable resin composition), droplets containing a thermosetting resin (thermosetting resin composition), and the like are excellent in workability. From the above, the use of an ionizing radiation curable resin composition is preferred. The thermosetting resin composition and the ionizing radiation curable resin composition are not particularly limited, and conventionally known ones can be used.

(S17)
Next, the substrate coated with the seal layer forming solution is transferred to the belt conveyor A, and the substrate conveyed to the droplet discharge device 3c is taken into the droplet discharge device 3c by the belt conveyor A. In the droplet discharge device 3c, as shown in FIG. 8, the liquid crystal material 56 is applied to the liquid crystal layer forming region A surrounded by the coating film 59a of the sealing layer forming solution (S17).

Here, the liquid crystal material 56 is not particularly limited, and a conventionally known material can be used.
Liquid crystal modes include TN (Twisted Nematic), STN (Super Twisted Nematic), HAN (Hybrid Alignment Nematic), VA (Vertical Alignment), MVA (Multiple Alignment). OCB (Optical Compensated Bend) type and the like.

The liquid crystal material may contain a spacer. The spacer is a member for keeping the thickness (cell gap) of the liquid crystal layer constant. The spacer material is not particularly limited, and conventionally known materials can be used.
In addition to the liquid crystal material, a functional liquid containing a spacer may be applied before or after the liquid crystal material is applied.

(S18)
Next, as shown in FIG. 9A, the substrate on which the liquid crystal material 56 has been applied is conveyed into a vacuum chamber 90a of the bonding apparatus, and the inside of the chamber 9a is evacuated and then sucked onto the lower surface plate 80a. Fixed. On the other hand, the substrate (upper substrate) 52b on which the color filter 62, the black matrix 64, the overcoat film 66, the common electrode 68, and the liquid crystal alignment film 70 (these are omitted) is placed on the upper surface plate 80b. The lower substrate 52a and the upper substrate 52b are bonded together by sucking and fixing (S18).

  Specifically, the alignment when the lower substrate 52a and the upper substrate 52b are bonded can be performed while recognizing the alignment marks provided in advance on the lower substrate 52a and the upper substrate 52b with a camera. At this time, in order to increase alignment accuracy, it is preferable to perform alignment by setting the distance between the lower substrate 52a and the upper substrate 52b to about 0.2 to 0.5 mm.

(S19)
Next, a curing process is performed on the laminate obtained by bonding the lower substrate 52a and the upper substrate 52b. The curing process is performed using a curing device (S19). Examples of the curing device include an ionizing radiation irradiation device and a heating device. In this embodiment, an ultraviolet irradiation device 82 is used. That is, as shown in FIG. 9B, ultraviolet rays are irradiated by the ultraviolet irradiation device 82 to cure the seal layer 59a.
Next, the reduced pressure in the chamber 9a is released to atmospheric pressure, and the adsorption of the lower substrate 52a and the upper substrate 52b is released.

  Thereafter, a polarizing plate is disposed on the outer surface of the liquid crystal cell, that is, the other surface side of each substrate constituting the liquid crystal cell, and the polarization direction thereof coincides with the rubbing direction of the liquid crystal alignment film formed on one surface of the substrate. Paste them so that they are orthogonal. Here, as a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film called an H film that absorbs iodine while stretching and aligning polyvinyl alcohol is sandwiched between cellulose acetate protective films or H A polarizing plate made of the film itself can be mentioned.

As described above, the liquid crystal display device shown in FIG. 3 can be manufactured.
Since the obtained liquid crystal display device has the liquid crystal alignment film formed by applying the composition of the present invention by the droplet discharge device 3a, the liquid crystal display device becomes a high quality and low cost liquid crystal display device.

In this embodiment, the liquid crystal alignment film is formed by a method of performing a rubbing process in S15. For example, a method of irradiating polarized radiation disclosed in Japanese Patent Application Laid-Open No. 2004-163646. The liquid crystal alignment ability can also be given by the above.
In this embodiment, in S17, a liquid crystal layer is formed by applying a liquid crystal material using the droplet discharge device 3c. However, two substrates on which a liquid crystal alignment film is formed are produced. Two substrates are arranged opposite to each other with a gap (cell gap) so that the rubbing directions in the respective liquid crystal alignment films are orthogonal or antiparallel, and the peripheral portions of the two substrates are bonded using a sealant. In addition, liquid crystal may be injected and filled in the cell gap defined by the substrate surface and the sealing agent, and the injection hole may be sealed to form a liquid crystal layer.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
(Examples 1-6, Comparative Examples 1-3)
As the first organic solvent A, N, N-dimethyl-acetamide, γ-butyrolactone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N, N-dimethyl-2-imidazolidinone, propylene carbonate One kind or plural kinds selected, and as the second organic solvent B, 1-methoxy-2-propanol, 1-methoxy-2-acetoxypropane, butyl cellosolve, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol monobutyl ether, One kind or plural kinds selected from diethylene glycol monobutyl ether acetate and diethylene glycol dibutyl ether were used and mixed at a ratio shown in the following table to obtain a mixed solvent. And the polyimide was melt | dissolved in each of the obtained mixed solvent, and the composition for liquid crystal aligning film formation of Examples 1-6 and Comparative Examples 1-3 was produced, respectively (solid content concentration 4 weight%).

The obtained composition for forming a liquid crystal alignment film was applied on an ITO substrate so as to have a dry film thickness of 100 nm using a droplet discharge device, and a liquid crystal alignment film was formed.
The resulting liquid crystal alignment film was observed for unevenness (straight irregularities and bumps at the edge portion) by visual observation, and evaluated as ○ when the film was well formed and × when the film was not formed. The results are summarized in the following table.

From the results shown in the table, the boiling point [t _max (A)] of the organic solvent having the highest boiling point among the organic solvents constituting the first organic solvent A is the organic solvent constituting the second organic solvent B. Among these, in the film forming method using the composition for forming a liquid crystal alignment film (Examples 1 to 6) higher than the boiling point [t _max (B)] of the organic solvent having the highest boiling point, there is no unevenness and the like is uniform. A satisfactory liquid crystal alignment film could be formed.
On the other hand, in the film forming method using the liquid crystal alignment film forming composition (Comparative Examples 1 to 3) having a boiling point [t _max (B)] higher than the boiling point [t _max (A)], the film formation is sufficient. Therefore, a satisfactory liquid crystal alignment film could not be formed.

It is a figure which shows an example of the liquid crystal display device manufacturing line which concerns on embodiment. 1 is a schematic view of an ink jet type ejection device according to an embodiment. It is a sectional side view which shows schematic structure of the liquid crystal display device which concerns on embodiment. It is a flowchart of the manufacturing method of the liquid crystal display device which concerns on embodiment. It is manufacturing process explanatory drawing of the liquid crystal display device which concerns on embodiment. It is manufacturing process explanatory drawing of the liquid crystal display device which concerns on embodiment. It is manufacturing process explanatory drawing of the liquid crystal display device which concerns on embodiment. It is manufacturing process explanatory drawing of the liquid crystal display device which concerns on embodiment. It is manufacturing process explanatory drawing of the liquid crystal display device which concerns on embodiment.

Explanation of symbols

  I ... Liquid crystal display device production line, 3a, 3b, 3c ... Discharge device, 22 ... Inkjet head, 24 ... Head body, 34 ... Discharge product (liquid crystal alignment film forming composition), 50 ... Liquid crystal display device, 56 ... Liquid crystal Layer, 60, 70 ... Liquid crystal alignment film, A ... Liquid crystal layer forming region

Claims (7)

A composition for forming a liquid crystal alignment film used when forming a liquid crystal alignment film by a droplet discharge method,
A mixed solvent containing a first organic solvent A having a surface tension of 32 mN / m or more and a first organic solvent B having a surface tension of less than 32 mN / m, and a liquid crystal alignment film forming material dissolved in the mixed solvent; , Containing
The first organic solvent A and the second organic solvent B are each composed of a single type or a plurality of types of organic solvents,
Of the organic solvents constituting the first organic solvent A, the boiling point of the organic solvent having the highest boiling point is t _max (A), and among the organic solvents constituting the second organic solvent B, the boiling point is highest. Assuming that the boiling point of the organic solvent is t _max (B), the first organic solvent A and the second organic solvent B in the mixed solvent are expressed by the following formula: t _max (A)> t _max (B)
A liquid crystal alignment film-forming composition characterized by satisfying   2. The composition for forming a liquid crystal alignment film according to claim 1, wherein a mixing ratio of the second organic solvent B in the entire mixed solvent is 1 wt% or more and 50 wt% or less.   The first organic solvent A is N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N, N-dimethyl-2-imidazolidinone, N, N-dimethyl-acetamide, γ-butyrolactone, propylene carbonate The composition for forming a liquid crystal alignment film according to claim 1, wherein the composition is at least one selected from the group consisting of:   The second organic solvent B is at least one selected from the group consisting of 1-methoxy-2-propanol, 1-methoxy-2-acetoxypropane, butyl cellosolve, diethylene glycol ethyl methyl ether, and diethylene glycol diethyl ether. The composition for forming a liquid crystal alignment film according to any one of claims 1 to 3.   The solid content concentration is 1% by weight to 10% by weight, the viscosity is adjusted to 3 mPa · s to 20 mPa · s, and the surface tension is adjusted to 30 mN / m to 45 mN / m. The composition for liquid crystal aligning film formation as described in any one of 1-4. The material for forming a liquid crystal alignment film has the following formula (I)

(Wherein P ¹ is a tetravalent organic group, Q ¹ represents a divalent organic group), and the following formula (II)

(Wherein P ² is a tetravalent organic group and Q ² represents a divalent organic group), and is a polymer having at least one selected from repeating units represented by Item 6. The composition for forming a liquid crystal alignment film according to any one of Items 1 to 5.   A liquid crystal display device comprising a step of applying the composition for forming a liquid crystal alignment film according to any one of claims 1 to 6 onto a substrate surface by a droplet discharge method to form a liquid crystal alignment film. Manufacturing method.

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